Trigger mechanism



' 14, 1945- J. c. GARAND 82.3

TRIGGER MECHANISM Filed July 29, 1942 2 Sheets-Sheet 1 14, 1945- .1. c.GARAND TRIGGER MECHANISM Filed July 29, 1942 2 Sheets-Sheet 2 LT 121-11-1. EL GUIELI'Ld which:

Patented Aug. 14, 1945 UNITED STATES PATENT OFFICE-1 j .2 v 2,352,410 Ti TRIGGER MECHANISM John C. Garand, Springfield, Mass. ApplicationJay-29, 1942, Serial No. 452,769

(Granted under the act of March 3,, 18 83, as amended April 30, 1928;3700.'G.757)

14 Claims.

The invention described herein may bemanufacturedandused by'or'for theGovernment for governmental purposes, without the payment to me of anyroyalty thereon.

--This invention relates to a trigger mechanism for an'automatic.firearm and particularly to sucha firearm which is to be fired onlysemiautomatically.-

' An object of this invention is to produce an improved triggermechanism for firearm. A'particularf object of this invention is toproduce a semi-automatic firing trigger mechanism which will maintainits semi-automatic characteristics even, though a faulty cartridge maybe fired which does vnotprovide sufiicient energyto drive the boltmechanism through its'completecycle. lA further object of this inventionis to provide a semi-automatic firing trigger mechanism having animproved, positive acting safety.

m The specificnature of the invention as well as other objects andadvantages thereof will clearly appear from a description of apreferred'embodi- 'ment'as-shown'in the accompanying drawings inFigureil is a longitudinal sectional view of .the trigger mechanismshown in the cocked position. Figure-2 isalongitudinal section view ofthe trigger mechanism shownwith the trigger released. I

Figure 3 is a longitudinal sectional view showing-the trigger in thereleased position and the operating rod at the end of the bolt recoilmovement."

Figure 4 is aright end'elevational view partly in section of :Figure 3.v

Figure 5 is a perspective view of the sear. Figure 6 is a perspectiveview of the detent.

, The trigger mechanism to be described is pariticularly adaptable foruse in'an automatic firearm of the general type described in detail inmy copending application, Serial No. 426,036,

filed January8, 1942, but it should be understood that this improvedtrigger mechanism is equally adaptable for use in any automaticfirearmwherein a reciprocating bolt member is utilized. i

. 'As shown in Figure 1 in assembled relation, the improved triggermechanism comprises a trigger frame member I. The forward 'end'of theframe member I comprises two sidewalls l a and lb which, with a forwardend wall (not shown) de- -cocked position of the firearm. l

le and at the extreme-rear end of the iramea countersunk hole I isprovided. The rear p01? tion of the trigger mechanism maybe secured tothe receiver and the stock by means of a bolt passing through the holeIf and threaded into the receiver and/or the stock (not'shownl When thetrigger frame is assembled toafiree arm, the rear portion of the frameshould under lie the path of the reciprocating bolt member utilized inthe particular firearm or in the. path of a member secured to such boltwhich-recipro cates therewith, such for example, as an. operating rod 2which is shown diagramatically in the drawings. This rod 2 is secured tothe bolt in any desired manner. Such member should be provided with-afront-facing surface 2a suitable for engagement byasear. 7

The sear 3 is pivotallymounted in the .top rear portion of the framechamber 1 d on. a. transverse pm It! which is supported bythe sidewallsIa and l b of the trigger frame. The pivoted-end of the sear 3 isbifurcated. and an opening 3a inthe sear is thereby provided. A magazinelatch 5' is also mounted on the pin It, the latch having arearwardlyextending projectionj The :projection 5a extends into the opening 312provided in the sear and a hole 5b in such-extension permits themagazine latch to be pivotally mounted on the pin l0. The-sear 3extends-rear- ,wardly from its pivoted mounting and in its centralportionis provided with a sear shoulder 3b which engages the-latchingsurface-2aon the operating rod to hold the operating. rod.in,. the

The rear portion of the sear 3 is provided with a pair of dependingears3c. Between suchears the top portion of a trigger 4 is pivotallymounted as by the rivet or in M which extends'through the depending ears3c. Atrigger springfi has one endinserted in a spring chamber ,llaprovided in the trigger 4 and itsotherend engages a spring seat 301provided in the rear face of the sear 3 and above'the rivet l4.- Thevspring 6 thereby exerts a force tending to pivotally separatethe-trigger 4 and the sear -3.- Such-separation is prevented by thefront-surface of the trigger 4 engaging a transversepin 8 mounted in thetrigger frame I underneath the trigger 4. The trigger 4 extends throughthe trigger notch In in the frame I into the space defined byuthetrigger guard portion Ie of the frame I. The portion of the triggerextending into this space is of conventional shape. The rear. surfaceof, the

trigger 4 is provided with stepped surfaces :41) .and 40, respectivelythe upperand lower of such steps. A fulcrum or detent member 1 is provided to engage such step surfaces to permit the operation of thetrigger mechanism. The detent member 1 is of approximate T-shape havinga bifurcated stem 1a inclined with respect to the head 11). Thebifurcated stem 1a surrounds the trigger 4 and is pivotally mounted inthe trigger frame I on transverse pin 8, A U-shaped torsion spring 9 iswrapped around the pin 8 and exerts a force between the trigger frame Iand the detent 1, biasing the detent in a clockwise direction as viewedin Fig, l. v edge 10 of the head lb is thereby biased into engagementwith the notch of the top trigger step surface 4b. In this position thehead 1b-of the- 1 in the notch of the step surface 4b eithetrig ger 4provides a fulcrum point permittin the operation of thetri-gger. Thuson-pul-lingthe trigger 4, it pivots about the edge'le lowering theextreme forward end of the trigger and thereby pivoting the sear3'counterclockwise about the pin 10. This leverage arrangement providesthe primary trigger pressure. After slightpivotal movement of thetrigger under the trigger pull applied, a projection 4d, formed by the'base of -step 40, contacts surface 111 at the 3 base of the bifurcatedportion of the detent 1. This contact point now, acts as the *fulcrumfor th trigger andsupplies a-secondary trigger pressure of roughly twiceas great due to shift inposi- :tion of the trigger fulcrum. This changeof f-ulcrum does not affect the path of movement of the sear 3 anditcontinues to pivot counterclockwise about the pin in. Thus thesearnotchSb is pulled out of engagement withthelatching-surface 2a onthe operating rod 2, permitting the operating rod to drive forward under'the influence of the operating-spring to fire the firearm. Upondischarge of a cartridge, the operating rod The forward I 2 beingsecured to the blolt (not s'hown) isdri'ven rapidly to, the rear. Thehottomrear surface 21) of the rod engages the top of the head 1b of thedetent 1 and as the rear movement of the detent 1 is continued,thedetent 1 is forcibly pivoted in a counterclockwise direction. Thispivoting removes the forward edge 70 of the detent from engagement withthe notch of the step thin the trigger and surface'ld ofthe detent fromengagement with projection Ad. If the trigger has been released by thistime, the sear assumes its cocked positionunder the influence of thespring 6 and the next cartridge may he fired by pulling the trigger. Ifhoweverthere is still a pullingforce exerted on the trigger at thistime, the removal of the detent from the rear of the trigger destroysthe fulcrum on which the trigger was pivoted and the fulcrum for thetrigger lever system then becomes the pin 14. :Henceithe sear 3 pivotsback into its'cockedposition under the influence of the spring -6 andthetrigger pull and engages the surface 2a of the operating rod as that"rnember drives forward, arresting it in the' -cofcked iDQsition. Theforward movement of the operating rod 2 of course frees-the detent 1 forclockwise pivotal, movement under the influence of spring 9. "If thetrigger is still pulled theend To tion as to insure thata-n'ew cartridgewill-be of the detent strikes the vertical surface of trigger step 40but this contact does not provide a fulcrum for the trigger which wouldpermit the operation of the trigger. Hence the trigger must be releasedwhereupon the detent edge 10 rides out of step 40 and into wedgingengagement in the notch of step 41) ready for another firing cycle. Ofcourse if the trigger has beenreleased when detent 1 is releasedfrom'the operating rod, then the detent edge 10 immediately pivots intothe notch of step 4b under the influence of spring fired, thus assuringsemi-automatic operation of the firearm.

' The safety mechanism for this improved trig- -ger constructionutilizes a spring ll common to the magazine latch 5. A vertical springchamber H is providedin the trigger frame I in the portion underlyingthe rearward magazine extension 5a. This chamber lg extends 'clearthrough-the frame I. :A spring H is mounted in thisch-am ber,'-the -topend'of the spring engaging theextension 5a, of the magazine latch whilethe bottom end of the sprin'gis' secured in a spring seatpdetent' 12which is inserted in the chamber 19 insuchfa manner as topermit'vertical movement of the detent l2 with respect to the frame I.The detent I2 is held up 'in the chamber M-by the safety slide 13.Thisslide l3 'is-mourited-in oppositely disposed horizontal grooves lkprovided in thebottom of the-side walls I c an-c1 lb of-the triggerframe. The top surface of the safety slide 13 supports the detent I12irrespective of the position'of the safety slide I3. i This topsurfaceofthe safety slide l3 i s given a, sawtooth configuration'asindicated at Ma. The bottomsurf-ace of the detent 42 is correspondinglyshaped; Thus by engagement of such surfaces the safety slide 13is-resiliently secured in either a forward or a rearward position by thedetent 1.2. "Attached to the central portion of the safety guide and--projecting vertically upward between the frame side walls Ia and lb is'alocking extension 13b. In arearwar'd position of the safety1l3, thisextension is brought directly under two small depending projections 3eprovided respectively-on the bottom of the ears 3c of the sear 3. Withthe safety slide in this rearward position, pivotal movement of the searin a direction to'release the se'ar'notchflb from engagement with theoperating rod 2is prevented by the projections 3estriking the safetylock l3b. In the forward position of the safety slide 1'3, the'safetylock 13b is moved out of the path of the sear projection 3eand hence thetrigger mechanism is rendered operative. An integrally formed arm of thesafety slide projects below the slide portion'zand terminates in ahorizontal button =l3d which reciprocatesthrough a hole lm in the frontend of thetrigger' guard 1c. The safety may thus be readily manipulatedbythe operator of the firearmflsince it may begrasped by his triggerfinger.

A special feature of the foregoing construction lies in the fact that itis not possible to obtain The position of the detent 1 with respect tothe operatingrod 2 ean'be so designed that the detent 'Iis pivoted outof engagement with the notch of the step surface 41) of the trigger whenthe operating rod has reached such a rearward posipicked up by the bolton its forward movement.

Hence each time that there is sufiicient recoil movement of theoperating rod 2 to load a new cartridge into the chamber of the firearmthe detent 1 will be pivoted out of engagement with both the notch 41)and the projection 4d of the triggerand hence the sear 3 will bereleased to returnto its cocked position under the bias of spring 6.Thus any recoil movement of the bolt and operating rod sufficient toproduce the loading of a cartridge will also return the sear to itscocked position, preventing the uncontrolled firing of such cartridge.

I claim:

1. A trigger mechanism for a firearm comprising a trigger frame, a scarpivotally mounted to the trigger frame, a trigger pivotally secured tothe sear, compressed first resilient means mounted between the triggerand sear, stop mean on said trigger frame for limiting the pivotalmovement of said trigger under the bias of said first resilient means, afulcrum member pivotally mounted on the trigger frame, said fulcrummember having one portion arranged to engage a first fixed area on therear of said trigger, a

second resilient means biasing said fulcrum member into engagement; withsaid trigger thereby roviding a first fulcrum about which the triggermay be initially pulled to pivot said sear about its mounting and asecond portion on said fulcrum member engageable by a second fixed areaon the rear of said trigger after limited pulling movement of saidtrigger thereby providing a second fulcrum for further pivotal movementof said trigger. v

2. A trigger mechanism for a firearmv compris ing a trigger frame, asear pivotally mounted on the trigger frame, a trigger pivotally securedat its forward end to the rear end of the sear, a compressed springmounted between said trigger and sear, a transverse pin in the triggerframe limiting the movementof the trigger under such spring bias, anotch on rear of said trigger, a detent pivotally mounted on said pinand resiliently biased into engagement with said notch on the rear ofthe trigger thereby providing a fulcrum about which the trigger may bepulled to pivot said sear about its mounting.

3. A trigger mechanism for a firearm comprising atrigger frame, asearpivotally mounted to the trigger frame, a trigger pivotally securedto the sear, compressed first resilient means mounted between thetrigger and sear, stop means on said trigger frame for limiting thepivotal movement of said trigger under the bias of said first resilientmeans, a detent hav g a bifurcated portion surrounding said trigger,said detent being pivotally mounted to the trigger frame at the end ofits bifurcated portion, a second resilient means biasing said detentinto engagement with the rear surface of the trigger to provide afulcrum for prim'ary trigger pull, a projection on said trigger lyingwithin the bifurcated portion of the detent, said projection arranged toengage said detent after slight movement. of the trigger to therebyprovide a fulcrum for secondary triggerpullr portion surrounding saidtrigger, said detent being pivotally mounted on said transverse pin atthe end of its bifurcated portion, resilient means biasing said detentinto engagement with the rear surface of the trigger to provide afulcrum for primary trigger pull, a projection on said trigger lyingWithin the bifurcated portion of the detent, said projection arranged toengage said detent after slight movement of the trigger to therebyprovide a fulcrum for secondary trigger pull.

5. In an automatic firearm, in combination, a recoiling memberreeiprocable in a straight line path, a trigger frame, a sear pivotallymounted to the trigger frame and arranged to engage said recoilingmember near the forward end of its movement, a trigger pivotally securedto the sear, compressed first resilient means mounted between thetrigger and sear, operating to bias said sear into a cooked positionrelative to said recoiling member, stop means on said trigger frame forlimiting the pivotal movement of said trigger under the bias of saidfirst resilient means, a notch on the rear of said trigger, a T-shapeddetent having its base pivotally secured to the trigger frame, a secondresilient means pivotally biasing the forward end of the head of saiddetent into engagement with said notch on the rear of said triggerthereby providing a fulcrum about which the trigger may be pulled topivot the sear,

the rear end of the head of said detent projecting into the recoilpath'of the recoiling member and actuated thereby to remove said detentoutof engagement with the trigger notch thereby permitting the sear toreturn to its cocked position under the bias of said first resilientmeans.

6. In an automatic firearm havinga recoiling member, a trigger mechanismcomprising a trigger frame, a sear pivotally mounted on the trig gerframe, a trigger pivotallyv secured at its forward end to the rear endof the sear, a compressed spring mounted between said trigger and sear,a transversepin in the trigger frame limiting the movement of thetrigger under spring bias, a T-shaped detent having a bifurcated stemportion surrounding said trigger, said detent being pivotally mounted onsaid transverse'pin at the end of its bifurcated portion, a notch'on therear of said trigger, resilient means pivotally biasing the forward end.of-the head of said detent into engagement with said notch on the rearof said trigger, thereby providing a fulcrum about which the triggermaybe pulled to pivot the sear, the rear end of the head of said'detentarranged to project into the recoil path of the recoiling member, saiddetent being pivoted out of engagement with the trigger by recoilmovement of the recoiling memberv thereby permitting the sear to returnto its cocked position under the bias of said compressed spring.

'7. In an automatic firearm having a recoiling member. a triggermechanism comprising a trig er frame, a sear pivotally mounted to thetrigger frame, a trigger pivotally secured to the sear, compressed firstresilient means mounted between the triggerand sear, stop means on saidtrigger frame for limiting the pivotal movement of said trigger underthe bias' of said first resilient means, a T-shaped detent having abifurcated detent into engagement with said notchon' the rear. of saidtrigger thereby providing a fulcrum about' 'which .the:;=t i enimayzbeninitia-lly; pulled to pivotth'e sear; ax projectionaorrthe rearof said tri ger -lyingiwithina the bifurcated portion, of the detent,said.- projection: engaging said. Ldetent: by movement; of: the" triggeruto' thereby ,lprovide; a fulcrum for secondary: triggerzpull, the rearend of the head of. said: detent arranged'lto; project into, the recoil:path. of saidxrecoiling member, said detent beings-pivoted entirely" outf "engagement with, the-trigger:by recoilrmovement of'therecoiling-member' thereby permitting the sear to return "to its cockedposition under" the bi'asuof saidfirst resilient-means. vI u 8; -In' varr, automaticifirearm, ,in combination, a recoiling:mem'berreciprocable in a straight :line path, :a trigger frame, a sear:pivotally mounted orr'fthe trigger frameand' arrangedzto engage saidrecoiling "member nearrthe forward end of its movement; a; trigger:pivotally secured to :the sear,

comp'ressedifirstresilient"means-mounted between the? trigger: and searand operatingv to' bias 'said searinto aco'cked positiomrelative to saidr'ecoiling membenrstop means onsaid'trigger frame for limitingthepivotal movement of said trigger under 'the 'bias ofJsaid-i firstresilient means, a

Ti-shaped detentihaving titsiba'se pivotally secured to theitriggerframe; a 'first notchlo'ni-the' rear' of saidtriggen' a second resilientmeans pivotally biasing; the forward end or the header-said detentrintorengagementwith a said. first notch on the: rearof said?trigger thereby providing a fulcrum about which the trigger maybe pulledto pivot'the sear; a second notchbn the-rear-of the triggeradjacent'thersaid first notch; the rear end of the'head of said-'dete'n't.piojebtingdhtb the recoil'path of the-recalling member andactuated thereby to remove said detent out of engagement with thetrigger thereby permitting the sear'to return to its cocked positionunder the bias of said'first' resilient means, said second notcharranged to be engaged by the forward end of the head of said detent ifthe trigger-remains pulled after the recoiling member returns to cockedposition; thereby requiring release'of the trigger pull to render thetrigger operative.

9. In'an automatic firearm having a recoiling member, a triggermechanism comprising a trigger frame; a sear pivotally mounted on thetrigger frame a trigger pivotally secured 'at'its forward end tothe-rear end of the sear, a compressed spring-mounted between saidtrigger and sear, a transversepin-in the trigger frame limiting themovement ofthe trigger under such spring bias, a T-shaped detent havinga bifurcated stem portion surrounding said trigger, saiddetent beingpivotally'mounted on said transverse pin at the end of its bifurcatedportion, 'a first notch on the rear-of said trigger, resilient meanspivotally biasing the forward end of the head of'saiddetent intoengagement with saidfirst notch on the rear ofsaid trigger, therebyproviding a' fulcrum about which the trigger may be pulled to pivot thesear, a second notch on the rear of the trigger adjacent the said firstnotch, the rear end of the head of said detent arranged to project intothe recoil path of said recoiling membensaid detent being pivoted out ofengagement with the trigger by recoil movementof the recoiling memberthereby permitting the sear to return to its cocked position'under thebias of said compressed spring, said second notch arranged to be engagedby the forward end of the head of said detentif the trigger remainspulled after the recoilingmember returns to battery position, therebyrequiring release of the trigger 'pullrto render the trigger operative.

10. :Inran Cautomaticifimamm having a recoiling memben'zartriggerrmechanism; comprising-re: trigger: frame; a", sear: pivotallyanount'edto 113118, trigger framaia trigger pivbt'al'ly, securedtoathe'sear,compressed? first resilientx'means: i mounted betweem the ..trigger:uandzssear; a'stop ,:means on said trigger: frame for gliiniting the:pirzot'al movement of said triggerEmnderithe bias: bf'rsaid?firstres'ilient ;nieans;i aaxT-shapedidetent: having a bifurcated stemportion surrounding said trigger, said detent being pivoltally securedto: the 'trigger frame at the end of its l'aifu'rcatedi n1tion,' a firstnotch on the rear of said triggeria'second resil-. ient means pivotallybiasing the forwardaendr' of the headsv of :said': detent". into:engagement with said first not'chpn the rear' ofsaidtrigger therebyproviding a fulcrum about which the trigger maybe initially pulled topivot thesean arsed 0nd notch on; the rear 1 of said' trigger; aprojection on therear of: said trigger lyingi betweeni'the bifurcatedpor tion of the tdetenhtsaid projection arranged to engage said detentby movem'en'tzof the trigger' to" thereby provide' a ful'crumr forsecondary trigger pull, the rear end of the headi of said detentarranged-to'project into therecoil path of the 1 recoiling member, saiddetent being pivoted out of engagement "with thei triggerwby recoilmovementpf the recoiling member thereby permitting the sear to return toit's-cocked position under the bias 0f said first res'ilint m'eans, saidsecondnotch arranged to be engaged bytm forward end of the head Ptifsaid detent if the trigger remains pulledafter the recoiling memberreturnsto battery 'pos'itiom thereby requh ing release of the triggerpull to renderjthetriE- eroperative. i

Y 11. In a' magazine Ffirearm, the"- combination' -of a trigger" framedefinihg' amagazine opening; a magazine latch piv'otally -mounted in-theframe adjacent said magazine opening, a rearward projection on saidlatch, a -pivot'ed sear, "a safety member slidably mounted in thetrigger frame uriderf the sear, an upstanding lOcR ing=rnember on' saidsafety adapted to engage said sear n one position of said safety, aplurality-oinotches in the top surfac'e of said safety m m eranddisposed alongthe line of movementgthereofi avertically movabledetentinounted in the trigger frame above said'safety member and' havinga base'shaped to engage any oneof said' notches, said d'etent arrangedto "engage one said notch at the sear engaging position-of said safetymembnand a compressed spring mounted' between said detenta'nd said"magazine latch-projection. 1 12." In'a magazine firearm; the combinationof 'a trigger f r ame,'aipiv oted magazine latch, a pivoted sear, asafety me nber slidably mounted in said trigger frame beneath-saidsearformovement' between two positionsrespectively of engagement andnon-engagement" withsaid sear, a detent member rnovablymounted; in'saidtrigger frame and arfranged'to' engagesa'id safety member in either of:its two; positions, and a compressed spring mounted bet'weerr saiddetent member and saidfmagaz ji'ne latch, said spring operating-tohold'sa'id' detent-member in engagement with saidsafety member andtoimparta pivotal biasftojsaidmagazine-latch.

s z e fire rm; h 'wmb ria i n jof a tri err me; af a a i l i t nivp lymounted on a'transverse pin inthe trigger frame, a sear pivotallymounted on said transverse pin,

a safety memberfslidably mounted inf said' trigger frame beneath saidsear for" movement b tweentwo positions respectively of engagement andnon-engagement with said sear, a detent member movably mounted in saidtrigger frame and arranged to engage said safety member in either of itstwo positions, anda compressed. spring mounted between said detentmember and said magazine latch, said spring operating to hold saiddetent member in engagement with said safety member and to impart apivotal bias to said magazine latch.

14. In an automatic firearm in combination, a recoiling memberreciprocable in a straight line path, a trigger frame, a sear pivotallymounted on the trigger frame and arranged to engage said recoilingmember near the forward end of its movement, a trigger pivotally securedto said sear, resilient means mounted between said trigger and said searand operating to bias said sear into a cooked position relative to saidrecoiling member, stop means on said trigger frame for limiting thepivotal movement of said trigger under the bias of said first resilientmeans, means engaging said trigger to provide a fulcrum about which saidtrigger may be pulled thereby pivoting said sear out of its cockedposition, said last mentioned means including a projection extendinginto the recoil path of said recoiling member and actuated thereby toremove said last mentioned means from engagement with said trigger,thereby permitting said sear to return to its cocked position under thebias of said resilient means to engage said recoiling member 15 in itsforward movement.

J O'H'N C". GARAND.

